The CNAP service, also known as calling information service, is a value-added service. The application of the CNAP service is as follows: When a user originates a call as a calling party, the service system sends the calling information set by the calling party, for example, a business card and greetings, to a mobile station (MS) of a called party by means of a flash message, so that the called party can obtain the calling information visually. The user can customize the calling information by scenarios, for example, the user can send different calling information to different called parties in different time segments and in different areas, by setting individualized filter rules. Flash messages are a type of short messages. Unlike a traditional short message, which is displayed only after a user presses some keys, a flash message is displayed directly on the screen of a called MS when the flash message is received, and the flash message is generally not saved after the flash message is displayed.
The CNAP service is different from the calling line identification presentation (CLIP) service. In the CLIP service, the switching system sends the calling number to the called MS, and the called MS displays the calling number directly or displays the calling name corresponding to the calling number in the phonebook of the called MS. If the phonebook of the called MS does not store the calling user information corresponding to the calling number, the called MS only displays the calling number. Moreover, the called party is even unable to see the calling number if the called party has not subscribed to the CLIP service. In contrast to the CLIP service, the CNAP service is set by the calling party. When the calling party dials a called number, the service system sends the calling information to the called MS to facilitate the called party in identifying the calling party.
The prior call process of the CNAP service is briefly described below, and includes the following steps.
(1) A calling MS sends a call request to a switching system.
(2) The switching system determines that the call needs to trigger the CNAP service, and sends a calling information request to a calling information server. At the same time or after receiving a response returned by the calling information server, the switching system connects the call to the called MS.
(3) The calling information server stores the calling information set by the calling party. According to the calling information request sent by the switching system, the calling information server sends the calling information through a flash message to the called MS for displaying.
In researching the prior art and the practice process, the inventor of the present invention discovers that the sending of the calling information is independent of the connecting of the called MS after the CNAP service is triggered by the call in the foregoing call process. This makes it difficult to ensure the calling information to be sent to the called MS at a proper time, and cannot help the called party to identify the calling party in some cases. For example, if the calling information is sent to the called MS before the called MS rings, while the called party is answering another call at the moment or another incoming call is received, misunderstanding may be caused to the called party; or, if the calling information is sent to the called MS after the conversation between the calling party and the called party already begins or finishes, the CNAP service is then insignificant with respect to helping the called party to know the calling information beforehand.